1. Field of the Invention
Embodiments of the present invention relate to a method for manufacturing integrated circuit devices. More particularly, embodiments of the present invention relate to a method of providing activated precursors gases to a rapid cycle deposition process.
2. Description of the Related Art
Atomic layer deposition (ALD) is based on the exchange of chemical molecules or atoms between alternating reactants to deposit monolayers of material on a substrate surface. The monolayers maybe sequentially deposited one over the other to form a film composed of a plurality of individual layers to provide a desired film thickness. Typically, the alternating reactant is introduced into a processing chamber having a substrate in which a film is to be deposited is disposed therein, separately from a different reactant. A purge gas and pump system are used between pulses of alternately introduced reactants to prevent any overlap or coreaction between the reactants other than on the substrate. Each separate deposition step theoretically goes to saturation and self terminates, depositing at least a single molecular or atomic monolayer of material. Accordingly, the deposition is the outcome of a chemical or physical reaction between each of the alternating reactants and the substrate surface.
Compared to bulk deposition processes, such as chemical vapor deposition (CVD) and physical vapor deposition (PVD) for example, ALD is a slow process. Slower rates of deposition are not helpful toward achieving competitive performance and productivity. Since ALD reactions follow the kinetics of molecular-surface interaction, one solution to increase the deposition rate is to increase the kinetics of the molecular-surface interactions. The kinetics of molecular-surface interactions depends on the individual reaction rate between reactants and the substrate surface on which the materials are deposited. Therefore, the kinetics of molecular-surface interactions can be increased by increasing the reactivity of the individual reactants.
A common approach to increasing gas reactivity is to decompose the gas, generating ions/radicals that are highly reactive, especially at lower temperatures. This form of gas decomposition can be accomplished using various techniques, of which plasma technology is well known. Plasma technology generates high energy electrons that partially decompose and/or ionize the reactant gases and can be powered using various sources, such as microwave and radio frequency (RF), for example.
However, cyclical deposition processes utilizing plasma generation to activate reactant gases suffer many drawbacks. A major drawback is the ability to sustain a plasma of reactive gases within a processing chamber during the deposition process. Cyclical deposition processes, such as ALD, require rapid, repetitive pulses of reactants sometimes as fast as 300 milliseconds or less. Often, when the reactive gases are pulsed into a processing chamber, the plasma in the chamber is depleted or extinguished and must be re-established prior to a subsequent cycle. In a quest to increase product throughput, time does not allow for the repeated regeneration or re-ignition of a plasma between each step of the deposition process.
There is a need, therefore, for a cyclical deposition process capable of repeatably and reliably delivering activated gases to a processing chamber.